The patella is generally a flat, triangular bone located on the front of the knee joint. It is supported in the tendon of the quadriceps. The patella serves to protect the front of the knee and increase the leverage of the quadriceps.
During certain forms of surgery involving the knee, such as the implantation of a knee joint prosthesis, the natural patella may be resected for subsequent implantation of an artificial patella component. In one example, a patellar implant may be formed entirely of polyethylene. In some instances however, it may be difficult to stabilize such an implant relative to the surrounding tissue because a polyethylene surface may not be conducive to bone or soft tissue ingrowth. Consequently, securement of an entirely polyethylene patellar implant to a host patella may rely entirely on external fasteners such as sutures.
In another example, a patellar implant may comprise a polyethylene component having a porous metal backing secured by bone cement. In some cases however, the use of bone cement may present drawbacks. Application of bone cement may require careful placement and accuracy when locating the adhesive. Such a requirement may increase having excess bone cement entering the surrounding tissue and increase the surgery time.